Three-dimensional structure and stoichiometry of Helmintosporium victoriae190S totivirus
- Department of Estructura de Macromoleculas, Centro Nacional de Biotecnologia, CSIC, Campus Universidad Autonoma de Madrid, Darwin no 3, Cantoblanco, E-28049 Madrid (Spain)
- Imaging Sciences Laboratory, CIT, NIAMS, NIH, DHHS, Bethesda, MD 20892-5624 (United States)
- Centro de Investigaciones Biologicas, CSIC, 28006 Madrid (Spain)
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546 (United States)
Most double-stranded RNA viruses have a characteristic capsid consisting of 60 asymmetric coat protein dimers in a so-called T = 2 organization, a feature probably related to their unique life cycle. These capsids organize the replicative complex(es) that is actively involved in genome transcription and replication. Available structural data indicate that their RNA-dependent RNA polymerase (RDRP) is packaged as an integral capsid component, either as a replicative complex at the pentameric vertex (as in reovirus capsids) or as a fusion protein with the coat protein (as in some totivirus). In contrast with members of the family Reoviridae, there are two well-established capsid arrangements for dsRNA fungal viruses, exemplified by the totiviruses L-A and UmV and the chrysovirus PcV. Whereas L-A and UmV have a canonical T = 2 capsid, the PcV capsid is based on a T = 1 lattice composed of 60 capsid proteins. We used cryo-electron microscopy combined with three-dimensional reconstruction techniques and hydrodynamic analysis to determine the structure at 13.8 A resolution of Helminthosporium victoriae 190S virus (Hv190SV), a totivirus isolated from a filamentous fungus. The Hv190SV capsid has a smooth surface and is based on a T = 2 lattice with 60 equivalent dimers. Unlike the RDRP of some other totiviruses, which are expressed as a capsid protein-RDRP fusion protein, the Hv190SV RDRP is incorporated into the capsid as a separate, nonfused protein, free or non-covalently associated to the capsid interior.
- OSTI ID:
- 20779479
- Journal Information:
- Virology, Vol. 347, Issue 2; Other Information: DOI: 10.1016/j.virol.2005.11.038; PII: S0042-6822(05)00781-6; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0042-6822
- Country of Publication:
- United States
- Language:
- English
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